Photographic negative.



UNITED STATES PATENT OFFICE.

JOSEPH THACHER CLARKE, F HAIKBQW, ENGLAND. ASSIGNOR TO EASTMAN KODAK I 00., OF ROCHESTER, NEW YORK, A CORPORATION OF NE YORK.

PHOTOGRAPHIC NEGATIVE.

No Drawing.

To all whom it may concem:

Be it known that I, JosErI-r Tnncnnn CLARKE, a citizen of the United States, temporarily residing at Harrow, in the county of Middlesex, England, have invented certain Improvements in Photographic Negatives; and I do hereby declare the following to be a full, clear, and ex'act description of the same.

My present invention relates to photography and has for its object to provide an improved negative for photographic printing of'su'ch nature that it is particularly adapted for use in connection with ordinary negatives in printing at one operation composlte photographs or those containing two or more sub ects matter. The principal use for a negative of this description is.to enable a. portrait photographer of limited means to carry in stock a supply of cheap auxiliary negatives containing tones and half-tones or gradations of light and shade of subjects which will form desirable backgrounds for his finished prints and which may be readily adapted to his negatives, thus giving him the opportunity of selecting for the subject of the ne ative made by him, a suitable backgroun or setting without the necessity of carrying the usual expensive accessories 3 of a portrait gallery. It is desirable that,

the stock or background negatives adapted for this use be capable of alteration or modification to the negatives made by the operator, by very simple operations not requiriug the services of highly skilled operators or retouchers.

To these ends the'invention consists generally in a stock negative adapted for photographic printing embodylng a support of transparent or translucent material and preferably flexible, such as celluloid, gelatin or paper and having the desired scene, de

sign or pattern printed thereon in the re r quired varying degrees of density, in an ink or pigmented substance which is lmpervious ganese in the form of a fine powder of Specification of Letters Patent. .Patented hlar. 14, 1911. Application filed December'5, 1908' Serial No. 466,065.

brown or sepia tone, insoluble in water,and well suited for non-actlmc blocking out.

\V hen an ink of this material is painted over with dilute oxalic acid or dilute sulfuric acid, or a combination of the two, the coloring matter is discharged and the result is the production of a substance which is water soluble, translucent and almost white,and

printing blocks, such as are used for mechanical printing or otherwise, excepting that lights and shadows of the finished picture are reversed. In other Words, I form a positive printing block or the image-may be transferred and printed upon the support by lithography. The, ink or pigment is formed by mixing the powdered hydrated oXid of manganese with a suitable menstruum such,

for instance, as boiled linseed oil, or if desired, water, and I then ink the block and make an impression therefrom upon the suitable transparent or translucent support, such as celluloid, gelatin or paper and allow it to dry. This completes the back round of auxiliary negative and any desire nu1nber can, of course, be printed. from the blocks in the usual manner.

The exposure for the principal negative made by the photographer and tube used in connection with my auxiliary negatives is made with the subject against a black or very dark scene, which gives almost transpa renev for the background upon the negative and having he takes one of my background negatives and viewing the images on both negatives by u-ausmitted light, arranges his subject-tin proper position onthe background and secures the background negative in position by gummed strips or'otherwise:

finished his negatlve 'lben leok?ng through the combined negatires with the inked face of the auxiliary negative toward him, the operator with a tine brush, applies to the inked surface, where. it overlies the figure on the principal negative. the discharging chemicalreagent described, rendering the auxiliary negative transparent or translucent at these olnts. it is desirable that the operator da over the strokes of his brush with a bit of blotling pape'r, thus removing the colorless salt 5 The term lranslurent employed herein is so that only the transparent or translucent 5 intended tomean that quality of permitting portion of the paper or film \.1ll remain the passage of actinic light rays suliicient over the portrait image. The combined .negative may now be printed from in the usual mannerand as the principal negative has not been altered in any way, other l I E prin s with different backgrounds may be 5 made by applying other background neg:

tives and treating them in a-similar mannen.

Differentmaterials mighfb'e employed for the ink or pigment in which the-auxiliary and I do not, therefore, desire to be confined to that described but it is eminently desirable that it be such' a one that it may bereadily removed or its property of re sistance to the passage of actinic light rays be eliminated by the application of :rchemical reagent which can be readily applied by the operator without the exercise of greatskill and without'scratching or leaving 'narks liable to show in. the finished print.

The method of forming the auxiliary negatives 18 not material to the substance, of my invention, but as the material which I piefer to-use, viz., the hydrated oxid ofmanganese is in a form which permits it to be used with a'smtable menstruum to form ferring-this method will be obvious. F0- substantially the same reasons I prefer to or background negative is printed Ixm' ink for mechanical printing and as the implications may be readily made by the use of a printing-press, the reasons for preemploy paper as the support for the negative, but other transparent or translucent material. such as celluloid or gelatin, may

be used.

for ohservatioi'i and for negative printing whether or not it is absolutely transparent a translucentsupport having a design or r pattern printed thereon in an ink which is impervious to actinic light rays and having the characteristicthat its pigmentmay be dLsI-narged or rendered translucent by the chemical action of a reagent applied thereto.

.\s an article of nmnufacture, a neg:-

live for photographic printing embodying a translucent support having a design or pattern printed thereon in tones and halflones or lig'ldhiid shade in an ink normally impervious to actiniclight rays a-ud having the. eharaelerisiies that its pigment may be rendered. translncei'it by the chemical action of a reagei'it applied thereto.

3. As an article of manufacture, a negalive for photographic printing embodying a translucent support having a design or pattern printed tlu-reou in an ink containing hydrated oxid of manganese.

.lUHl'Illl '1'] [A CHER CLARKE. Witnesses:

lh 1m. li. (ilHl-l-ll'lf, llAH LX) ll. SIWMS 

